A defiant Donald Trump has blamed his worsening campaign struggles on "phony polls" from the "disgusting" media, as he fights to energise his most loyal supporters with his prospects of winning the presidency shrinking.

A defiant Donald Trump has blamed his worsening campaign struggles on "phony polls" from the "disgusting" media, as he fights to energise his most loyal supporters with his prospects of winning the presidency shrinking.

With 14 days to go until election day, the Republican nominee campaigned in battleground Florida as his team conceded publicly as well as privately that crucial Pennsylvania may be slipping away.

That would leave a razor-thin pathway to the 270 electoral votes needed to win the White House on November 8.

Despite continued difficulties with women and minorities, Mr Trump is refusing to soften his message in the campaign's final days to broaden his appeal, and offered an optimistic front in the middle of a three-day tour through Florida as thousands began voting in person.

"I believe we're actually winning," he said during a round-table discussion with farmers gathered next to a local pumpkin patch.

A day after suggesting the First Amendment to the Constitution may give the press too much freedom, he insisted that the media are promoting biased polls to discourage his supporters from voting.

"The media isn't just against me. They're against all of you," he told cheering supporters later in St Augustine. "They're against what we represent."

With Mr Trump on the defensive, Democrat Hillary Clinton worked to slam the door on his candidacy in swing state New Hampshire while eyeing a possible Democratic majority in the Senate.

The former secretary of state campaigned alongside New Hampshire governor Maggie Hassan, who is running for the Senate, and Massachusetts senator Elizabeth Warren, who was merciless as she seized on Mr Trump's history of predatory sexual language and several allegations of misconduct.

"He thinks that because he has a mouth full of Tic Tacs, he can force himself on any woman within groping distance," Ms Warren claimed. "I've got news for you Donald: Women have had it with guys like you."

Mr Trump has denied a pile of recent allegations, and he addressed a new one in an interview with WGIR radio in New Hampshire.

He called the allegations "total fiction" and lashed out at former adult film performer Jessica Drake, who said on Saturday that he had grabbed and kissed her without permission and offered her money to visit his hotel room a decade ago.

The Republican National Committee ignored him altogether in mailshots to New Hampshire voters set to be distributed later this week, according to material obtained by the Associated Press. The mail focuses instead on Ms Clinton's credibility, featuring a picture of her and former president Bill Clinton and the words "No More of The Lying Clintons".

Mr Trump's team has publicly acknowledged in recent days that he is behind.

His campaign manager Kellyanne Conway outlined a path to 270 electoral votes on Sunday that banks on victories in Florida, Ohio, Iowa and North Carolina along with New Hampshire and Maine's second congressional district.

Assuming he wins all of those - and he currently trails in some - he would earn the exact number of electoral votes needed to win the presidency and no more.

Noticeably absent from the list was Pennsylvania, a state that a senior adviser privately conceded was slipping away despite Mr Trump's aggressive courtship of white working-class voters.

Florida was largely the focus on Monday as in-person early voting began across 50 counties, including the state's largest. Remaining counties will start in the coming week.

Early voting by mail has been under way for weeks. Nearly 1.2 million voters in Florida have already mailed in ballots.

Ms Clinton plans to visit on Tuesday and Wednesday, while her running mate, Virginia governor Tim Kaine, was making two Florida appearances on Monday. He took a shot at Florida Republican senator Marco Rubio in the first, a reminder that Ms Clinton's team is fighting to retake a Senate majority.